U.S. patent number 10,100,700 [Application Number 15/182,697] was granted by the patent office on 2018-10-16 for cantilevered flow distributing apparatus.
This patent grant is currently assigned to Tenneco Automotive Operating Company Inc.. The grantee listed for this patent is Tenneco Automotive Operating Company Inc.. Invention is credited to William Adams, Michael Golin, Meng-Huang Lu, Daniel J. Owen, Fulun Yang, Yanping Zhang.
United States Patent |
10,100,700 |
Zhang , et al. |
October 16, 2018 |
Cantilevered flow distributing apparatus
Abstract
An exhaust aftertreatment system may include a housing, an
aftertreatment device, and a cantilevered flow distributing
element. The housing receives exhaust gas output from an engine and
has a main body and an exhaust gas inlet that is angled relative to
the main body. The flow distributing element is disposed within the
housing upstream of the exhaust aftertreatment device and includes
a baffle plate and a collar. The baffle plate is attached to an
inner wall of the main body. The collar may include a plurality of
first apertures, a downstream axial edge and an upstream axial
edge. A portion of the downstream axial edge may abut an
upstream-facing surface of the baffle plate. The baffle plate may
have a plurality of second apertures extending through the
upstream-facing surface. The collar may extend across and partially
block at least some of the second apertures.
Inventors: |
Zhang; Yanping (Livonia,
MI), Yang; Fulun (Ann Arbor, MI), Golin; Michael
(Dexter, MI), Owen; Daniel J. (Parma, MI), Adams;
William (Parma, MI), Lu; Meng-Huang (Ann Arbor, MI) |
Applicant: |
Name |
City |
State |
Country |
Type |
Tenneco Automotive Operating Company Inc. |
Lake Forest |
IL |
US |
|
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Assignee: |
Tenneco Automotive Operating
Company Inc. (Lake Forest, IL)
|
Family
ID: |
57537507 |
Appl.
No.: |
15/182,697 |
Filed: |
June 15, 2016 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20160376969 A1 |
Dec 29, 2016 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62186159 |
Jun 29, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01N
3/103 (20130101); F01N 3/0253 (20130101); F01N
3/021 (20130101); B01F 5/0689 (20130101); F01N
3/2066 (20130101); F01N 3/2892 (20130101); B01F
3/04049 (20130101); F01N 3/206 (20130101); F01N
13/0097 (20140603); B01F 5/0473 (20130101); B01F
5/0688 (20130101); F01N 2470/18 (20130101); Y02T
10/24 (20130101); F01N 2610/02 (20130101); Y02T
10/12 (20130101); F01N 2240/20 (20130101); F01N
2470/04 (20130101) |
Current International
Class: |
F01N
1/00 (20060101); F01N 3/021 (20060101); B01F
3/04 (20060101); B01F 5/06 (20060101); B01F
5/04 (20060101); F01N 3/025 (20060101); F01N
3/20 (20060101); F01N 13/00 (20100101); F01N
3/28 (20060101); F01N 3/00 (20060101); F01N
3/02 (20060101); F01N 3/10 (20060101) |
Field of
Search: |
;60/286,301,303,324 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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101371016 |
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Feb 2009 |
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CN |
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105378245 |
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Mar 2016 |
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CN |
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105452624 |
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Mar 2016 |
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CN |
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4121940 |
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Jan 1993 |
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DE |
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102008031136 |
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Jan 2010 |
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DE |
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2607641 |
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Jun 2013 |
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EP |
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2009030560 |
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Feb 2009 |
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JP |
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2009228484 |
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Oct 2009 |
|
JP |
|
Primary Examiner: Wongwian; Phutthiwat
Assistant Examiner: Tran; Diem
Attorney, Agent or Firm: Harness, Dickey & Pierce,
P.L.C.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application
No. 62/186,159, filed on Jun. 29, 2015. The entire disclosure of
the above application is incorporated herein by reference.
Claims
What is claimed is:
1. An exhaust aftertreatment system comprising: a housing receiving
exhaust gas output from a combustion engine and having a main body
and an exhaust gas inlet that is angled relative to the main body;
an exhaust aftertreatment device disposed within the main body; and
a cantilevered flow distributing element disposed within the
housing upstream of the exhaust aftertreatment device, the flow
distributing element including a baffle plate and a collar fixed to
the baffle plate, the baffle plate including a radially outer
periphery that is attached to an inner circumferential wall of the
main body, the collar having a plurality of first apertures, a
downstream axial edge and an upstream axial edge opposite the
downstream axial edge, at least a portion of the downstream axial
edge abuts an upstream-facing surface of the baffle plate, the
baffle plate having a plurality of second apertures extending
through the upstream-facing surface, the collar extending across
and partially blocking at least some of the second apertures,
wherein the upstream-facing surface of the baffle plate extends
axially upstream such that a central portion of the upstream-facing
surface is disposed upstream relative to the radially outer
periphery of the baffle plate.
2. The exhaust aftertreatment system of claim 1, wherein the
downstream axial edge of the collar includes a plurality of
attachment zones that are circumferentially spaced apart from each
other, wherein the attachment zones are locations at which the
downstream axial edge is welded to the baffle plate.
3. The exhaust aftertreatment system of claim 2, wherein the
downstream axial edge includes a plurality of buffer zones, each of
the buffer zones including a circumferentially extending segment of
the downstream axial edge that abuts the upstream-facing surface
and is disposed between and directly adjacent to one of the
attachment zones and one of a plurality of open zones, wherein the
open zones are circumferentially extending segments of the
downstream axial edge that extend across and partially block some
of the second apertures.
4. The exhaust aftertreatment system of claim 3, wherein each of
the attachment zones includes a tab that projects into one of a
plurality of slots in the baffle plate, and wherein the welds are
applied along circumferential lengths of the tabs.
5. The exhaust aftertreatment system of claim 4, wherein a sum of
circumferential lengths of all of the attachment zones is 32%-36%
of a total circumference of the downstream axial edge of the
collar.
6. The exhaust aftertreatment system of claim 5, wherein a sum of
circumferential lengths of all of the attachment zones and all of
the buffer zones is 64%-68% of the total circumference of the
downstream axial edge of the collar.
7. The exhaust aftertreatment system of claim 6, wherein a sum of
circumferential lengths of all of the open zones is 32%-38% of the
total circumference of the downstream axial edge of the collar.
8. The exhaust aftertreatment system of claim 1, wherein the collar
is a tubular member that extends entirely around a longitudinal
axis of the baffle plate.
9. The exhaust aftertreatment system of claim 1, wherein the collar
extends circumferentially around only a portion of a longitudinal
axis of the baffle plate.
10. The exhaust aftertreatment system of claim 1, wherein the
exhaust aftertreatment device is one of a particulate filter, an
oxidation catalyst and a selective catalytic reduction
catalyst.
11. An exhaust aftertreatment system comprising: a housing
receiving exhaust gas output from a combustion engine and having a
main body and an exhaust gas inlet that is angled relative to the
main body, the housing defining an end chamber at an intersection
of longitudinal axes of the main body and the inlet; an exhaust
aftertreatment device disposed within the main body downstream of
the end chamber; and a cantilevered flow distributing element
disposed within the housing upstream of the exhaust aftertreatment
device, the flow distributing element including a baffle plate and
a collar fixed to the baffle plate, the collar extending into the
end chamber, the baffle plate including a radially outer periphery
that is attached to an inner circumferential wall of the main body,
the collar having a plurality of first apertures, a downstream
axial edge and an upstream axial edge opposite the downstream axial
edge, at least a portion of the downstream axial edge abuts an
upstream-facing surface of the baffle plate, the baffle plate
having a plurality of second apertures extending through the
upstream-facing surface, the collar extending across and partially
blocking at least some of the second apertures, wherein the
upstream-facing surface of the baffle plate extends axially
upstream such that a central portion of the upstream-facing surface
is disposed upstream relative to the radially outer periphery of
the baffle plate.
12. The exhaust aftertreatment system of claim 11, wherein the
downstream axial edge of the collar includes a plurality of
attachment zones that are circumferentially spaced apart from each
other, wherein the attachment zones are locations at which the
downstream axial edge is welded to the baffle plate, wherein the
downstream axial edge includes a plurality of buffer zones, each of
the buffer zones including a circumferentially extending segment of
the downstream axial edge that abuts the upstream-facing surface
and is disposed between and directly adjacent to one of the
attachment zones and one of a plurality of open zones, and wherein
the open zones are circumferentially extending segments of the
downstream axial edge that extend across and partially block some
of the second apertures.
13. The exhaust aftertreatment system of claim 12, wherein each of
the attachment zones includes a tab that projects into one of a
plurality of slots in the baffle plate, and wherein the welds are
applied along circumferential lengths of the tabs.
14. The exhaust aftertreatment system of claim 13, wherein a sum of
circumferential lengths of all of the attachment zones is 32%-36%
of a total circumference of the downstream axial edge of the
collar.
15. The exhaust aftertreatment system of claim 14, wherein a sum of
circumferential lengths of all of the attachment zones and all of
the buffer zones is 64%-68% of the total circumference of the
downstream axial edge of the collar.
16. The exhaust aftertreatment system of claim 15, wherein a sum of
circumferential lengths of all of the open zones is 32%-38% of the
total circumference of the downstream axial edge of the collar.
17. The exhaust aftertreatment system of claim 11, wherein the
collar is a tubular member that extends entirely around the
longitudinal axis of the baffle plate.
18. The exhaust aftertreatment system of claim 11, wherein the
collar extends circumferentially around only a portion of the
longitudinal axis of the baffle plate.
Description
FIELD
The present disclosure relates to an exhaust aftertreatment system
having a cantilevered flow distributing apparatus.
BACKGROUND
This section provides background information related to the present
disclosure and is not necessarily prior art.
In an attempt to reduce the quantity of NO.sub.x and particulate
matter emitted to the atmosphere during internal combustion engine
operation, a number of exhaust aftertreatment devices have been
developed. Typical aftertreatment systems for diesel engine exhaust
may include a diesel oxidation catalyst (DOC), a diesel particulate
filter (DPF), and a selective catalytic reduction (SCR) catalyst, a
reductant injector and/or a hydrocarbon injector. A mixer or flow
distributing element is typically provided for mixing the injected
reductant or hydrocarbon with the exhaust gas upstream of a
catalyst or filter. Flow distribution elements may also spread the
flow over more surface area of the catalyst or filter to maximize
the effectiveness of the catalyst or filter. Without such exhaust
flow distributing elements, a percentage of catalyst or filter
surface area may be unused or underutilized.
While these systems may have performed well in the past, it may be
desirable to provide an improved flow distributing element that
more efficiently and effectively mixes the reductant or fuel with
the exhaust gas, has improved the structural durability and product
life, and does not create unacceptable backpressure within the
exhaust system.
SUMMARY
This section provides a general summary of the disclosure, and is
not a comprehensive disclosure of its full scope or all of its
features.
An aspect of the present disclosure provides an exhaust
aftertreatment device that may include a housing having an inlet,
an end chamber, a catalyst bed, and a cantilevered flow
distributing element disposed between the end chamber and the
catalyst bed. The cantilevered flow distributing element includes a
baffle plate and a cantilevered collar, the cantilevered collar
including a proximal end and a distal end, the proximal end being
affixed to the baffle plate at a plurality of attachment nodes. The
baffle plate includes a first plurality of apertures. The
cantilevered collar includes a second plurality of aperture. The
second plurality of apertures may be orientated substantially
perpendicular to the first plurality of apertures.
Another aspect of the present disclosure provides an exhaust
aftertreatment device that may include a first exhaust conduit
extending in a first axial direction and second exhaust conduit
extending in a second axial direction. The first axial direction
may be angled with respect to the second axial direction. The
second exhaust conduit may include an end chamber at an upstream
end of the second exhaust conduit, a catalyst at a downstream end
of the second exhaust conduit, and a cantilevered flow distributing
element disposed between the end chamber and the catalyst. The end
chamber is in fluid communication with the first exhaust conduit.
The cantilevered flow distributing element includes a baffle plate
and a cantilevered collar affixed to the baffle plate at a
plurality of attachment nodes. The baffle plate includes a first
plurality of apertures permitting exhaust gas to flow from the end
chamber to the catalyst. The cantilevered collar includes a second
plurality of apertures permitting exhaust gas to flow therethrough
in a direction perpendicular to the second axial direction.
Another aspect of the present disclosure provides an exhaust
aftertreatment system that may include a housing, an exhaust
aftertreatment device, and a cantilevered flow distributing
element. The housing may receive exhaust gas output from a
combustion engine and may have a main body and an exhaust gas inlet
that is angled relative to the main body. The exhaust
aftertreatment device (e.g., a particulate filter, an oxidation
catalyst and/or a selective catalytic reduction catalyst) is
disposed within the main body. The cantilevered flow distributing
element is disposed within the housing upstream of the exhaust
aftertreatment device. The flow distributing element may include a
baffle plate and a collar fixed to the baffle plate. The baffle
plate includes a radially outer periphery that may be attached to
an inner circumferential wall of the main body. The collar may
include a plurality of first apertures, a downstream axial edge and
an upstream axial edge opposite the downstream axial edge. At least
a portion of the downstream axial edge may abut an upstream-facing
surface of the baffle plate. The baffle plate may have a plurality
of second apertures extending through the upstream-facing surface
and a downstream-facing surface. The collar may extend across and
partially block at least some of the second apertures.
In some configurations, the downstream axial edge of the collar
includes a plurality of attachment zones that are circumferentially
spaced apart from each other. The attachment zones may be locations
at which the downstream axial edge is welded to the baffle
plate.
In some configurations, the downstream axial edge includes a
plurality of buffer zones. Each of the buffer zones includes a
circumferentially extending segment of the downstream axial edge
that abuts the upstream-facing surface and is disposed between and
directly adjacent to one of the attachment zones and one of a
plurality of open zones. The open zones are circumferentially
extending segments of the downstream axial edge that extend across
and partially block some of the second apertures.
In some configurations, each of the attachment zones includes a tab
that projects into one of a plurality of slots in the baffle plate.
The welds may be applied along some or all of the circumferential
lengths of the tabs.
In some configurations, a sum of circumferential lengths of all of
the attachment zones is 32%-36% of a total circumference of the
downstream axial edge of the collar.
In some configurations, a sum of circumferential lengths of all of
the attachment zones and all of the buffer zones is 64%-68% of the
total circumference of the downstream axial edge of the collar.
In some configurations, a sum of circumferential lengths of all of
the open zones is 32%-38% of the total circumference of the
downstream axial edge of the collar.
In some configurations, the upstream-facing surface of the baffle
plate extends axially upstream such that central portion of the
upstream-facing surface is disposed upstream relative to the
radially outer periphery of the baffle plate.
In some configurations, the collar is a tubular member that extends
entirely around a longitudinal axis of the baffle plate.
In some configurations, the collar extends circumferentially around
only a portion of a longitudinal axis of the baffle plate.
In some configurations, the housing defines an end chamber at an
intersection of longitudinal axes of the main body and the inlet.
The exhaust aftertreatment device is disposed within the main body
downstream of the end chamber.
In some configurations, the collar may extend into the end
chamber.
In some configurations, the baffle plate and the collar have
longitudinal axes that are coincident with the longitudinal axis of
the main body.
Further areas of applicability will become apparent from the
description provided herein. The description and specific examples
in this summary are intended for purposes of illustration only and
are not intended to limit the scope of the present disclosure.
DRAWINGS
The drawings described herein are for illustrative purposes only of
selected embodiments and not all possible implementations, and are
not intended to limit the scope of the present disclosure.
FIG. 1 is a schematic representation of a combustion engine and an
exhaust aftertreatment system according to the principles of the
present disclosure;
FIG. 2 is a top view of a housing of the exhaust aftertreatment
system with a cantilevered flow distributing element disposed
therein;
FIG. 3 is a cross-sectional view of the housing taken along line
3-3 of FIG. 2;
FIG. 4 is a perspective view of the cantilevered flow distributing
element;
FIG. 5 is another perspective view of the cantilevered flow
distributing element;
FIG. 6 is an enlarged view of a portion of the cantilevered flow
distributing element shown in FIG. 5;
FIG. 7 is perspective view of another cantilevered flow
distributing element according to the principles of the present
disclosure;
FIG. 8 is a perspective view of yet another cantilevered flow
distributing element according to the principles of the present
disclosure;
FIG. 9 is a perspective view of yet another cantilevered flow
distributing element according to the principles of the present
disclosure;
FIG. 10 is a perspective view of yet another flow distributing
element according to the principles of the present disclosure;
FIG. 11 is a perspective view of yet another cantilevered flow
distributing element according to the principles of the present
disclosure;
FIG. 12 is a perspective view of yet another cantilevered flow
distributing element according to the principles of the present
disclosure; and
FIG. 13 is a table including natural frequency values of flow
distributing elements with various design parameters.
Corresponding reference numerals indicate corresponding parts
throughout the several views of the drawings.
DETAILED DESCRIPTION
Example embodiments will now be described more fully with reference
to the accompanying drawings.
Example embodiments are provided so that this disclosure will be
thorough, and will fully convey the scope to those who are skilled
in the art. Numerous specific details are set forth such as
examples of specific components, devices, and methods, to provide a
thorough understanding of embodiments of the present disclosure. It
will be apparent to those skilled in the art that specific details
need not be employed, that example embodiments may be embodied in
many different forms and that neither should be construed to limit
the scope of the disclosure. In some example embodiments,
well-known processes, well-known device structures, and well-known
technologies are not described in detail.
The terminology used herein is for the purpose of describing
particular example embodiments only and is not intended to be
limiting. As used herein, the singular forms "a," "an," and "the"
may be intended to include the plural forms as well, unless the
context clearly indicates otherwise. The terms "comprises,"
"comprising," "including," and "having," are inclusive and
therefore specify the presence of stated features, integers, steps,
operations, elements, and/or components, but do not preclude the
presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof. The
method steps, processes, and operations described herein are not to
be construed as necessarily requiring their performance in the
particular order discussed or illustrated, unless specifically
identified as an order of performance. It is also to be understood
that additional or alternative steps may be employed.
When an element or layer is referred to as being "on," "engaged
to," "connected to," or "coupled to" another element or layer, it
may be directly on, engaged, connected or coupled to the other
element or layer, or intervening elements or layers may be present.
In contrast, when an element is referred to as being "directly on,"
"directly engaged to," "directly connected to," or "directly
coupled to" another element or layer, there may be no intervening
elements or layers present. Other words used to describe the
relationship between elements should be interpreted in a like
fashion (e.g., "between" versus "directly between," "adjacent"
versus "directly adjacent," etc.). As used herein, the term
"and/or" includes any and all combinations of one or more of the
associated listed items.
Although the terms first, second, third, etc. may be used herein to
describe various elements, components, regions, layers and/or
sections, these elements, components, regions, layers and/or
sections should not be limited by these terms. These terms may be
only used to distinguish one element, component, region, layer or
section from another region, layer or section. Terms such as
"first," "second," and other numerical terms when used herein do
not imply a sequence or order unless clearly indicated by the
context. Thus, a first element, component, region, layer or section
discussed below could be termed a second element, component,
region, layer or section without departing from the teachings of
the example embodiments.
Spatially relative terms, such as "inner," "outer," "beneath,"
"below," "lower," "above," "upper," and the like, may be used
herein for ease of description to describe one element or feature's
relationship to another element(s) or feature(s) as illustrated in
the figures. Spatially relative terms may be intended to encompass
different orientations of the device in use or operation in
addition to the orientation depicted in the figures. For example,
if the device in the figures is turned over, elements described as
"below" or "beneath" other elements or features would then be
oriented "above" the other elements or features. Thus, the example
term "below" can encompass both an orientation of above and below.
The device may be otherwise oriented (rotated 90 degrees or at
other orientations) and the spatially relative descriptors used
herein interpreted accordingly.
With reference to FIG. 1, an exhaust aftertreatment system 10 is
provided that may treat exhaust gas output by a combustion engine
12. The exhaust aftertreatment system 10 may include a housing 14,
a fluid delivery system 16, a cantilevered flow distributing
element 18, and one or more aftertreatment devices 20. The housing
14 may receive exhaust gas discharged from the combustion engine
12. Exhaust gas received by the housing 14 may flow through the
flow distributing element 18 and the one or more aftertreatment
devices 20 before being discharged to the ambient environment.
The aftertreatment devices 20 may include a diesel oxidation
catalyst (DOC), a diesel particulate filter (DPF), a
selective-catalytic-reduction (SCR) catalyst, and/or any other
exhaust aftertreatment component. The DOC may be utilized to
oxidize hydrocarbons and carbon monoxide of the exhaust gas and
oxidize nitrogen monoxide to nitrogen dioxide. The DPF may include
a catalyst support for trapping particulate matter (PM) entrained
in the exhaust gas, and the catalyst support eliminates the PM
through a chemical reaction. The SCR catalyst may convert nitrogen
oxides in the exhaust gas to nitrogen (N.sub.2), water and/or
carbon dioxide, for example.
The housing 14 may include a main body 22 and an inlet 24. The main
body 22 may be defined by a first longitudinal axis A1 (FIG. 3),
and the inlet 24 may be defined by a second longitudinal axis A2
(FIG. 3) that is angled relative to the first longitudinal axis A1.
While FIG. 3 depicts a ninety-degree angle between the first and
second longitudinal axes A1, A2, it will be appreciated that the
angle between the first and second longitudinal axes A1, A2 could
be greater than or less than ninety degrees. The flow distributing
element 18 and the aftertreatment devices 20 may be at least
partially disposed in the main body 22.
The fluid delivery system 16 may pump a fluid (e.g., a hydrocarbon
fuel or reductant such as urea or ammonia) from a tank 26 to an
injector 28 that may spray the fluid into the exhaust stream within
the housing 14 at or upstream of the flow distributing element 18.
The flow distributing element 18 may mix the fluid with the exhaust
gas to provide a more uniform mixture of the fluid and exhaust gas
before the mixture enters the aftertreatment device 20.
As shown in FIGS. 1 and 3, the flow distributing element 18 may be
disposed within the housing 14 at a location upstream of the
aftertreatment devices 20 (e.g., between the inlet 24 and the
aftertreatment devices 20). The flow distributing element 18 may
include a baffle plate (or partition plate) 30 and a collar (e.g.,
a tubular or semi-tubular cantilevered plate) 32. The baffle plate
30 may be fixed to an inner diametrical wall 33 of the main body 22
of the housing 14. The baffle plate 30 and collar 32 may be
centered on the first longitudinal axis A1 (i.e., longitudinal axes
of the baffle plate 30 and collar 32 may be coincident with the
first longitudinal axis A1). As shown in FIG. 3, the collar 32 is
fixed to the baffle plate 30 and may extend axially into an end
chamber 34 of the housing 14 (i.e., an area of the housing 14 at
which the first and second longitudinal axes A1, A2 intersect). In
this manner, the flow distributing element 18 separates the end
chamber 34 from the aftertreatment device(s) 20. The flow
distributing element 18 alters the flow characteristics of the
radially incoming exhaust gas from the inlet 24 to promote improved
uniformity of the flow prior to the exhaust gas interacting with
the aftertreatment device(s) 20 within the housing 14.
Referring now to FIGS. 3-6, the baffle plate 30 can be a circular
plate having a plurality of flow apertures 36 through which exhaust
gas can flow from the end chamber 34 to the aftertreatment
device(s) 20. The flow apertures 36 can have any shape and size,
including but not limited to circular, elliptical, or elongate. In
some configurations, the flow apertures 36 may include louvers (not
shown) that may create a swirling flow downstream of the flow
apertures 36. As shown in FIG. 3, a profile of the baffle plate 30
can be crowned or frusto-conical. In some configurations, an
upstream-facing axial end surface 38 (FIG. 4) of the baffle plate
30 is convex, and a downstream-facing axial end surface 40 (FIG. 5)
of the baffle plate 30 is concave). The flow apertures 36 extend
through the axial end surfaces 38, 40. In some configurations, the
baffle plate 30 may have a substantially flat or planar profile
(i.e., the axial end surfaces 38, 40 may be planar).
The collar 32 may be a rolled tube having a substantially
cylindrical shape. A downstream axial edge 42 of the collar 32 is
attached thereto via a plurality of attachment nodes 44. While the
particular configuration shown in FIGS. 4-6 includes eight
attachment nodes 44, the flow distributing element 18 could include
a different number of attachment nodes 44. An upstream axial edge
46 of the collar 32 extends into the end chamber 34 and is
unsupported. In this manner, the collar 32 is a cantilevered tube
within the housing 14. That is, the collar 32 is supported only at
the downstream axial edge 42 and is not supported by any other
structure elsewhere. In fact, the entire flow distributing element
18 may be cantilevered (i.e., supported only by the inner
circumferential wall 33 of the housing 14 at the radially outer
periphery of the baffle plate 30 and completely unsupported
elsewhere).
The collar 32 may include a plurality of flow apertures 48. As
shown in FIG. 4, the flow apertures 48 can have a circular shape or
an elongated obround shape, for example. It will be appreciated,
however, that the size, shape and arrangement of the flow apertures
48 may be chosen to promote specific flow characteristics (e.g.,
swirling). For example, some of the flow apertures 48 may be
elongated and angled 45 degrees with respect to the first
longitudinal axis A1. The elongated and angled flow apertures 48
may all be orientated in a common direction clockwise or
counterclockwise to promote a rotating flow, or they can be
orientated at one angle over a portion of the collar 32 and at a
different angle on another portion of the collar 32 so as to
promote flow toward a selected region of the exhaust aftertreatment
device(s) 20. The configuration of round flow apertures 48 and
elongated angled flow apertures 48 shown in FIGS. 2-4 may provide
several performance benefits. Namely, this configuration may
increase the flow of gas in and out of the collar 32, improve the
uniformity of the flow, reduce flow backpressure and increase the
stiffness of the collar 32.
In some configurations, the downstream axial edge 42 of the collar
32 includes one or more projecting tabs 50 and the baffle plate 30
includes a corresponding plurality of slots 52 sized to receive the
projecting tabs 50 therethrough, as shown in FIGS. 4-6. In such
configurations, welds may be formed along the projecting tabs 50 to
fixedly attach the collar 32 to the baffle plate 30. Positioning
the welds along the tabs 50 may reduce distortion of the collar 32
and/or baffle plate 30 as a result of the welding process. In such
configurations, the projecting tabs 50, slots 52, and welds define
the attachment nodes 44. In some configurations, the sizes and/or
locations of the tabs 50 and slots 52 can be configured to control
the orientation (e.g., the clocking) of the collar 32 relative to
the baffle plate 30 (i.e., the tabs 50 and slots 52 could be
configured such that the tabs 50 can only be inserted into the
slots 52 when the collar 32 is properly rotationally oriented
relative to the baffle plate 30). In some configurations, the
attachment nodes 44 could include additional or alternative joining
means. In some configurations, the downstream axial edge 42 of the
collar 32 may not include the projecting tabs 50 and slots 52 and
may abut the baffle plate 30 over its entire circumference and the
welds alone may define attachment nodes 44.
As shown in FIG. 6, the interface of the downstream axial edge 42
and the baffle plate 30 can be divided into zones including a
plurality of first zones 54, a plurality of second zones 56 and a
plurality of third zones 58. The first zones (attachment zones 54)
include the attachment nodes 44 at which the downstream axial edge
42 of the collar 32 is mechanically joined to the baffle plate 30.
In some configurations, the attachment zones 54 do not span,
intersect or abut any flow apertures 36 in the baffle plate 30. In
other configurations, one or more of the attachment zones 54 may
intersect the flow apertures 36.
In each of the second zones (open zones 56), the downstream axial
edge 42 of the collar 32 spans across one of the flow apertures 36
in the baffle plate 30. In the open zones 56, the downstream axial
edge 42 of the collar 32 may extend across and partially block the
flow of exhaust through the flow apertures 36, thereby reducing the
overall flow area through the baffle plate 30 and increasing
backpressure in the exhaust system. If a reduction in backpressure
is desired, the amount of the portions of the downstream axial edge
42 in the open zones 56 may be reduced to increase the flow area,
and thus reduce the backpressure. In some configurations, the
downstream axial edge 42 may have one or more apertures or cutouts
that are aligned with and open to one or more of the apertures 36
to reduce backpressure. Having the downstream axial edge 42
traverse some of the flow apertures 36 provides a further advantage
of premixing exhaust flow that has passed through the flow
apertures 48 with the exhaust flow that has not passed through the
flow apertures 48 before the combined flow travels through the flow
apertures 36. That is, three flow paths are define through each of
such flow apertures 36 that are traversed by the downstream axial
edge 42: (1) flow through the flow aperture 36 radially outside of
the collar 32, (2) flow through the flow aperture 36 that is
radially inside of the collar 32, and (3) flow through one of the
flow apertures 48 in the collar 32 before flowing through the flow
aperture 36.
The third zones (buffer zones 58) are the spaces located
circumferentially (i.e., angularly) between adjacent attachment
zones 54 and open zones 56. That is, each buffer zone 58 is defined
as the space that is circumferentially between one of the
attachment zones 54 and an immediately adjacent one of the open
zones 56. The buffer zones 58 do not span any portion of any of the
flow apertures 36 and act to increase the stiffness of the flow
distributing element 18.
Referring now to FIG. 7, another cantilevered flow distributing
element 118 is provided that may incorporated into the exhaust
aftertreatment system 10 instead of the cantilevered flow
distributing element 18. The flow distributing element 118 may be
similar or identical to the flow distributing element 18 described
above, except a baffle plate 130 of the flow distributing element
118 may include a configuration of flow apertures 136 that differs
from the configuration of flow apertures 36 in the baffle plate 30.
As shown in FIG. 7, all of the flow apertures 136 in the baffle
plate 130 have substantially the same diameters, unlike the flow
apertures 36 in the baffle plate 30, some of which have larger or
smaller diameters.
Referring now to FIG. 8, another cantilevered flow distributing
element 218 is provided that may be incorporated into the system 10
instead of the cantilevered flow distributing element 18. The flow
distributing element 218 includes a baffle plate 230 and a collar
232. The baffle plate 230 may be similar or identical to either of
the baffle plates 30, 130. The collar 232 may be similar or
identical to the collar 32, except that the collar 232 is not a
cylindrical pipe. Rather, the collar 232 is shown as a curved plate
spanning approximately 180 degrees around a center point of the
baffle plate 230 and disposed about the top half of the baffle
plate 230 (i.e., the half of the baffle plate 230 closest to the
inlet 24 of the housing 14).
Referring now to FIG. 9, another cantilevered flow distributing
element 318 is provided that may be incorporated into the system 10
instead of the cantilevered flow distributing element 18. The flow
distributing element 318 includes a baffle plate 330 and a collar
332. The baffle plate 330 may be similar or identical to either of
the baffle plates 30, 130, 230. The collar 332 may be similar or
identical to the collar 32, except that the collar 332 is not a
cylindrical pipe. Rather, the collar 332 is shown as a curved plate
spanning approximately 270 degrees around a center point of the
baffle plate 330 and disposed about the top portion of the baffle
plate 330 (i.e., the portion of the baffle plate 330 closest to the
inlet 24 of the housing 14).
FIG. 10 provides a flow distributing element 418 (or compact flow
modifier) that does not include a collar. The flow distributing
element 418 may include a baffle plate 430 that may be similar or
identical to the plates 30, 130, 230, 330.
FIG. 11 provides yet another cantilevered flow distributing element
518 that may be incorporated into the exhaust aftertreatment system
10 instead of the flow distributing element 18. The flow
distributing element 518 may include a baffle plate 530 and a
collar 532 that may be similar or identical to the baffle plate 30
and collar 32, except that the flow distributing element 518
includes two extended attachment nodes 544 that fix the collar 532
to the baffle plate 530. While the performance of the flow
distributing element 518 may be adequate in some applications, in
other applications, only two attachment nodes 544 for affixing the
collar 532 to the baffle plate 530 may fail to provide sufficient
structural support for the collar 532 and may adversely affect the
natural frequency of the flow distributing element 518.
FIG. 12 provides yet another cantilevered flow distributing element
618 that may be incorporated into the exhaust aftertreatment system
10 instead of the flow distributing element 18. The flow
distributing element 618 may include a baffle plate 630 and a
collar 632 that may be similar or identical to the baffle plate 30
and collar 32, except that the flow distributing element 618
includes six attachment nodes 644 that fix the collar 632 to the
baffle plate 630. While the performance of the flow distributing
element 618 may be adequate in some applications, in other
applications, having six attachment nodes 644 for affixing the
collar 632 to the baffle plate 630 may fail to provide sufficient
structural support for the collar 632 and may adversely affect the
natural frequency of the flow distributing element 618.
FIG. 13 is a chart showing the natural frequencies of exemplary
flow distributing element designs having different numbers of
attachment nodes. Resonant vibration may be a significant root
cause of fatigue failure of exhaust aftertreatment systems. If the
natural frequency of a flow distributing element is within
vibration frequency range of the engine 12, the flow distributing
element may be more likely to fail due to resonant vibration. For
example, for a ten-cylinder engine operating at highway speed, a
fifth order engine vibration frequency, which is the dominant
frequency, may be approximately 333 Hz. If flow distributing
element natural frequency is above 350 Hz (as is the case for
Design 4, for example, which has eight attachment nodes, like the
configuration shown in FIGS. 4-6), flow distributing element
resonant vibration will not occur, which results in improved
fatigue life for the flow distributing element. Increasing the
relative size of the attachment nodes will increase the flow
distributing element vibration frequency, and, thus, improve
structural rigidity of the flow distributing element. However, this
may result in a relatively smaller open zones which may increase
backpressure.
In some configurations, the cantilevered flow distributing element
18, 118, 218, 318 maximizes flow uniformity and structural rigidity
and simultaneously minimizes backpressure. Such performance can be
achieved by adhering to following general design parameters: (1) a
sum of the lengths (i.e., the circumferential lengths) of all of
the attachment zones 54 is 32%-36% of a total circumference of the
downstream axial edge 42 of the collar 32; (2) a sum of the lengths
(i.e., the circumferential lengths) of all of the attachment zones
54 and the buffer zones 58 (i.e., the sum of the combined lengths
of the welded and un-welded portions of the attachment nodes) is
64%-68% of a total circumference of the downstream axial edge 42 of
the collar 32; and (3) a sum of the lengths (i.e., the
circumferential lengths) of all of the open zones 56 is 32%-38% of
a total circumference of the downstream axial edge 42 of the collar
32.
The foregoing description of the embodiments has been provided for
purposes of illustration and description. It is not intended to be
exhaustive or to limit the disclosure. Individual elements or
features of a particular embodiment are generally not limited to
that particular embodiment, but, where applicable, are
interchangeable and can be used in a selected embodiment, even if
not specifically shown or described. The same may also be varied in
many ways. Such variations are not to be regarded as a departure
from the disclosure, and all such modifications are intended to be
included within the scope of the disclosure.
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